They are among the modelling industry’s most in-demand stars.
Gigi, 26, looked stunning in a black bra top and mini skirt as well as a donned a yellow open shirt and leather trousers which highlighted her toned midriff.
The star also sported a matching pair of trousers while she added height to her frame with silver boots.
Styling her brunette locks into a ponytail, Gigi added to her outfit with a black handbag and a pair of sunglasses.
Accentuating her beauty with a light pallet of makeup, Gigi completed her look with a light blue headband.
The model was also spotted making her way to the rehearsal session where she donned a pair of black leopard print shoes and a cream face mask.
Runway: Gigi, 26, donned a cream open shirt for the rehearsal day which highlighted her toned midriff
Strut: The Russian beauty also sported black trousers and a matching pair of shoes as she prepared for the show
Irina, 35, showed off her modelling skills as she took to the runway in a crisp white open shirt.
The Russian beauty also sported black trousers and a matching pair of shoes as she prepared for the show.
Letting her tresses fall loose down her shoulders, she also wore a light blue feathered piece in her hair.
Meanwhile, Gigi’s younger brother Anwar Hadid was seen on an outing in New York City on Wednesday.
Looking good: Gigi was seen out on a stroll as she made her way to the runway rehearsal
Casual: The star also sported a matching pair of trousers and black leopard print shoes
Trendy: Gigi also sported a pair of sunglasses for her day in the Italian city
The youngest member of the Hadid family sported a dark grey printed T-shirt and a matching pair of jeans.
Carrying a yellow suitcase, the model, who is in a relationship with singer Dua Lipa, took his pet dog Dexter for a walk.
On Tuesday, Gigi gave fans a behind-the-scenes look at her baby Khai’s first birthday extravaganza on her Instagram Stories. She shares the tot with her former One Direction bandmember boyfriend Zayn Malik.
The party was attended by Hadid’s entire family, including sister Bella and mother Yolanda, and held at her luxury apartment in New York City.
Wow: During the show, Gigi also donned a black crop top with a denim mini skirt and a matching jacket
Debut: She signed with IMG Models in 2013 and made her New York City Fashion Week debut in February 2014
Incredible: Gigi looked nothing short of sensational as she led the models strutting their stuff down the runway
Sultry: Irina (right) donned a black crop top with a black leather jacket and matching skirt
Stars: Other models in the show included Adut Aklech (far left) and Joan Smalls (centre left)
Colourful: Adut Aklech donned a multi-coloured shawl along with a teal dress with a patterned print
Stripes: Joan Smalls turned heads in a black and white striped shirt with matching trousers
Showstopper: Gigi waved to spectators watching the rehearsals
The first slide in Gigi’s post showed off the elaborate decorations setup on the patio of her apartment, including four large, gold balloons spelling out Khai’s name.
The balloon creations came in the form of a panda bear from the popular children’s animated show Word Party, which appeared to be the party’s dominant theme.
Some less impressive balloon displays, including a large number one to signify Khai’s first birthday, were scattered around the space.
Audience: Vogue editor-in-chief Anna Wintour donned a white long-sleeved dress with a red floral print
Sibling: Meanwhile, Gigi’s younger brother Anwar Hadid was seen on an outing in New York City on Wednesday
Stroll: The youngest member of the Hadid family sported a dark grey printed T-shirt and a matching pair of jeans
Success: Like his older sisters Gigi and Bella, Anwar has also worked as a model
Romance: Anwar is in a relationship with pop star Dua Lipa
Resting in the middle of the patio was a baby-safe enclosure that would allow the little one to hang out outdoors without getting into mischief.
The enclosure featured a small pale pink slide, an adorable hippo figurine, and blocks for Khai to play with as her guests mingled.
There was also a mini inflatable jumper with an attached ball pit for Khai to play in. ‘My baby turned one this weekend,’ captioned the runway maven on one of her posts.
At-home: On Tuesday Gigi gave fans a behind-the-scenes look at her baby Khai’s first birthday extravaganza on her Instagram Stories